ADM1191 returns wrong values of voltage and current

I use ADM1191 as a power meter (voltage and current) for motor control application. I init IC to continious convert both voltage and current, or voltage only, or current only. MCU reads values by I2C but returned voltage is less than measured at IC input by ~1.8 V (try from 12 V to 24 V) and current MSB (all 8 high bits) are zeros. It doesn't matter what way I get data - 3 bytes of both voltage and current or 2 bytes separate voltage and current. VRANGE is 0 (26.52 V), ALERT and SETV pins disconnected from MCU. Test on current about 260 mA with ~3 A max (Rsense = 0.033 Ohm), current code should be about 300.

As you can see the part is powered via VCC pin, and also use it to sense voltage and current (alone with sense pin). The Icc for this part is typ 1.7mA, combined with 1k resistor would give you a drop around 1.7V. This explains the voltage read back offset. Because of this voltage offset, the voltage on VCC would be lower than on SENSE, so your current reading would be zero.

I would suggest to remove the RC and may be filter the data digitally.

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As you can see the part is powered via VCC pin, and also use it to sense voltage and current (alone with sense pin). The Icc for this part is typ 1.7mA, combined with 1k resistor would give you a drop around 1.7V. This explains the voltage read back offset. Because of this voltage offset, the voltage on VCC would be lower than on SENSE, so your current reading would be zero.

I would suggest to remove the RC and may be filter the data digitally.